Association between osteoporosis and risk of dementia: a Korean women nationwide population-based cohort study.

Brief rationale: dementia and osteoporosis share risk factors and are rising in aging populations.

Main results: osteoporosis significantly increases the risk of all-cause dementia, Alzheimer's disease dementia, and vascular dementia in Korean older women. Significance of the paper: early detection and treatment of osteoporosis may reduce dementia risk.

Purpose: Dementia and osteoporosis share common risk factors and are increasing in prevalence in the aging population. This study aimed to investigate the impact of osteoporosis on dementia and its subtypes in women using data from a population-based, health-screening cohort, with a follow-up period of more than 10 years.

Methods: This retrospective study included 66-year-old Korean women who participated in the "National Screening Program for Transitional Ages" from 2010 to 2011. Participants were categorized based on spine bone mineral density T-scores into three groups: normal (T-score ≥ - 1.0 standard deviation [SD]; 18.7%), osteopenia (- 2.5 SD < T-score < - 1.0 SD; 42.5%), and osteoporosis (T-score ≤ - 2.5 SD; 38.8%). Incident dementia cases were evaluated until 2021 using national healthcare claims databases. Fine-Gray subdistribution hazard models were used to assess the risks of all-cause dementia including Alzheimer's disease (AD) dementia and vascular dementia (VaD), accounting for death as a competing risk.

Results: The study included 131,872 dementia-free women aged 66 years. Over an average follow-up of 10.4 ± 1.8 years, 9399 individuals developed all-cause dementia (7.1%). Osteoporosis was associated with increased risks for all-cause dementia (adjusted subdistribution hazard ratio [asHR] 1.14; 95% confidence interval [CI] 1.08-1.21; p < 0.001), AD dementia (asHR 1.14; 95% CI 1.08-1.22; p < 0.001), and VaD (asHR 1.42; 95% CI 1.08-1.87; p = 0.013), compared to normal.

Conclusion: Our findings highlight an association between osteoporosis and increased risks of developing all-cause dementia, AD dementia, and VaD. Further research is needed to explore the effects of early identification and treatment of osteoporosis in preventing dementia.